1. Technical Field
The inventions relate to apparatus and methods fig optical communication.
2. Discussion of the Related Art
This section introduces aspects that may be helpful to facilitating a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
In optical communication systems, a data stream is modulated onto an optical carrier, which carries the data from an optical transmitter to an optical receiver. One common method of optical data modulation involves amplitude modulation of the optical carrier, e.g., between ON and OFF states. Such optical amplitude modulation of the optical carrier may be performed by direct modulation of the laser that produces the optical carrier, e.g., by changing the biasing of the laser whose output is being modulated. Such optical amplitude modulation of the optical carrier may alternatively be performed by externally modulating the light beam output by a laser, e.g., with a variable optical attenuator.